Fluid-operated timer



June 11, 1963 R. w. WARREN 3,093,

FLUID-OPERATED TIMER Filed June 5, 1961 4 Sheets-Sheet 1 ill nu MENINVENTOR.

/5 Raymond W. Warren June 11, 1963 R. w. WARREN 3,093,306

FLUID-OPERATED TIMER Filed June 5, 1961 4 Sheets-Sheet 2 IN VEN TOR.

Raymond W Warren BY} 24;, 414%. i 5 M 4, q jp-l uzi.

R. W. WARREN FLUID-OPERATED TIMER June 11, 1963 4 Sheets-Sheet 5 FiledJune 5, 1961 INVENTOR. Raymund 14 Warren /Y. ,aifiwg a 2021x164; 4- 5.wa M June 11, 1963 R. w. WARREN FLUID-OPERATED TIMER 4 Sheets-Sheet 4Filed June 5, 1961 INVENTOR. Raymond W. Warren BYJ Ring y v. 1?. w 2 0Unite States arent 3,093,306 Patented June 11, 1953 i ce The inventiondescribed herein may be manufactured and used by or for the Governmentfor governmental purposes without the payment to me of any royaltythereon.

This invention relates to a fluid-operated timer which is capable ofindicating predetermined time intervals.

There are many kinds of timing devices in existence today. Electrical,electronic and mechanical timers are, of course, among the most wellknown. There are disadvantages inherent in each type of timer. Knownmechanical timing devices have the disadvantage of requiring numbers ofmoving parts in order to achieve a timing function. Wear, friction andthermal expansion constantly affect the functioning of these timingdevices as well as their accuracy.

Electrical or electronic timing devices on the other hand, requiresubstantially constant sources of electrical power. Such sources ofpower may not be either available or the most desirable type of powerunder particular operating conditions. Also such timing devices do nothave long operating lives.

In computers in particular, and in control systems in general, largenumbers of timing devices are utilized. The basic types of timers, thatis, electrical, electronic and mechanical are employed almostexclusively. This is so primarily because of the lack in the art of asuitable fluidoperated timer.

The inherent ruggedness and reliability of fluid systems as well as theavailability of air or water as a power source are among the reasons whyfluid operated systems are also desirable and may often be employed inlieu of pure mechanical, electrical or electronic systems. In order tosatisfactorily utilize fluid in fluid-actuated systems some satisfactorymeans for achieving amplification of a fluid input signal had to bedeveloped because of the energy losses occurring when the fluid isconveyed from one component to another in the system. Without means toamplify the fluid signal the size of the power source becomesexcessively large. Amplification of fluid input signals was achieved bysystems with numerous moving pistons and valves. Unfortunately, suchsystems have rather low response times because of the inertia of themoving valves or pistons.

The fluid-operated timer of this invention incorporates the combinationof a fluid-operated oscillator, a fluidoperated binary counter and afluid-operated AND com ponent. The fluid oscillator, counter and ANDcomponent require no moving parts other than the working fluid employedtherein for their operation.

A basic component of the fluid-operated timer is a fluid oscillator. Onetype of fluid oscillator incorporates a fluid amplifier and a feedbacksystem which communicates with the amplifier and feeds back energy tocontrol fluid flow from the amplifier. This type of oscillator, knownand referred to herein as a sonic oscillator, utilizes the effect ofwaves which travel at the speed of sound. It should be distinguishedfrom a relaxation type oscillator discussed hereafter which depends uponthe filling and emptying of a fluid capacitance or iner'tance to providethe desired timing or phase relationship.

The frequency of a sonic oscillator varies with the length of thefeedback path and the speed of sound. The speed of sound varies as forperfect gases or C= /KRT where R: gas constant T :temperature in degreesKelvin C=speed of sound (feet per second) K =ratio of specific heatsP=pressure in pounds per square inch =density.

During the operation of a sonic oscillator K varies between narrowlimits and as P increases, p increases. Consequently, the speed of soundfor slight variations in pressure and temperature is relativelyconstant. The length of the feedback path can easily be lengthened orshortened to provide any desired frequency of oscillation within thephysical limits of the system. A fluid amplifier is employed in thesonic oscillator and is preferably of the type which utilizes boundarylayer lock-on control. The following description is an aid inunderstanding some of the control principles involved in this type offluid amplifier.

In a boundary-layer-controlled fluid amplifier, a high energy power jetis directed towards a receiving aperture system by the pressuredistribution in the power jet boundary layer region. This pressuredistribution is controlled by the wall configuration of the interactionchamber, the power jet energy level, the fluid transportcharacteristics, the back-loading of the amplifier output passages andthe flow of control fluid to the boundary layer region. In this type offluid amplifier special design of the interaction chamber configurationcauses the power jet to lockon to one side wall and remain in thelocked-on flow configuration without a control fluid flow. When thepower jet is suitably deflected by a control fluid flow it can lockon tothe opposite side wall and remain in the locked-on flow configurationeven after the control fluid flow is stopped. Fluid amplifiers of theboundary layer control type control the delivery of energy of a mainstream of fluid to an outlet orifice or utilization device by means ofcontrol fluid flow issuing from a control nozzle generally at rightangles to the main stream. The proportion of the relatively high energymain stream delivered to an orifice may be varied as a linear ornon-linear function of the relatively low energy of a control streamintel-acting herewith. Since the energy controlled is larger than thecontrol energy supplied, an energy gain is realized and amplification inthe conventional sense is realized.

A fluid oscillator of the relaxation type requires in addition to afluid amplifier and a feedback system or loop, some means for storingfluid energy. Such oscillators may store fluid energy in two forms, aspotential and kinetic energy. Potential energy is energy associated witha fluid capacitance. The term fluid capacitance" can be defined as thatclass of fluid energy storage means which stores fluid potential energy.In general the energy stored in a fluid capacitance increases as aresult of introduciton of additional fluid therein. Fluid capacitancemay take one or more of the following forms: compression of the fluid toa greater density, change of thermodynamic state of the fluid, change ofelevation of the fluid, change of fluid internal energy level,compression of a second fluid separated from the first fluid by aflexible wall, compression of a second fluid in contact with the firstfluid, deformation of elastic walls which restrain the fluid, change ofelevation of the fluid, change of elevation of a weight supported by thefluid, and compression of bubbles or droplets of one fluid entrained inanother.

Fluids in motion have a kinetic energy which represents a second form ofstored energy. The method of storing energy in this form is toaccelerate the fluid to a higher speed. Fluid inertance is a measure ofthe pressure required to accelerate a mass of a fluid in a passageway ortube and is normally associated with the fluid flow through a tube.

The rate of oscillation of this type of oscillator varies with thepressure due to the change in rate at which the capacitance or inertancefills and discharges. Although the sonic oscillator, discussed above, ispreferred as a source for timed fluid pulses and is disclosed in detailin this application, oscillators of the relaxation type may also be usedas a source of timed pulses.

The second component of the timer of this invention consists of a fluidbinary counter. Such a counter comprises a series of fluid pulseconverters capable of performing functions analogous to those performedby sealers or flip-flops in electronic computers which are connectedtogether to form a fluid binary counter. Successive series of inputfluid signals cause determinable fluid flow patterns to occur in thepulse converters. Such flow patterns are utilized to actuate afluid-operated readout system.

The'third element comprising the fluid-operated timer of the instantinvention is a fluid readout component. This component preferably takesthe form of a fluid AND component. The fluid-operated AND component ofthis invention utilizes the amplifying and quick response capabilitiesof the fluid amplifiers of the afore-described boundary layer controltype. Such components produce a fluid output signal from a certainoutput tube when two or more input fluid signals of same minimummagnitude or energy level are received by the component at substantiallythe same time.

According to this invention the pulsed fluid output signals from a fluidoscillator are conveyed to a fluid-operated binary counter and hence toa fluid-operated AND component connected thereto. When the AND componentis properly connected to the counter the AND component will issue fluidpulses after predetermined intervals of time have elapsed. The instantinvention also includes an AND component for resetting the counter afterany time interval has elapsed so that a time cycle of any duration canbe produced.

Broadly, it is an object of this invention to provide a fluid-operatedtimer in which all elements comprising the timer except the Workingfluid remain stationary during operation thereof.

More specifically, it is an object of this invention to provide afluid-operated timer which comprises the combination of a source oftimed fluid pulses, means for counting these pulses and fluid operatedreadout means responsive to certain of such pulses.

Another object of this invention is to provide a fluid timer comprisinga fluid-operated counter and fluid-operated means for resetting thecounter so that any desired time interval can be produced.

Another object in accordance with the above object, is to provide afluid AND logic component as the fluidoperated means for resetting thecounter. A

The specific nature of the invention, as well as other objects, uses andadvantages thereof, will clearly appear from the following descriptionand from the accompanying drawing, in which:

FIG. 1 is a plan view of a fluid oscillator for providing timed outputfluid pulses.

FIG. 1A is an end view of FIG. 1.

FIG. 2 is a plan view of a fluid pulse converter for convertingsuccessive fluid pulses into alternating fluid output pulses.

FIG. 2A is a sectional side view of FIG. 2, taken through section lines2A2A.

FIG. 3 is a plan view of a fluid AND logic component for reading outfluid pulses from a fluid pulse converter.

FIG. 4 is a plan view of the fluid-operated timer of the instantinvention.

FIG. 5 is a plan view of another embodiment of a fluid AND componentwhich is employed to reset the timer of this invention.

FIG. 6 is a plan view of the fluid operated timer of this inventionwhich is capable of producing timed fluid pulses of any predeterminedduration.

The term input signal as used herein is the fluid signal which isintentionally supplied to the fluid component for the purpose ofinstructing or commanding the component to provide a desired outputsignal or flow pattern. The term output signal used herein is the fluidsignal or flow pattern which is produced by the component at its output.The input and output signals can be in the form of time or spatialvariations in pressure, density, flow velocity, mass flow rate, fluidcomposition, transport properties, or other thermodynamic properties ofthe input fluid individually or in combination thereof.

Referring now to FIG. 1 there is shown stable fluidoscillator 10 formedby three flat plates 11, 12, and 13 (FIG. 1A). Plate 12 is positionedbetween plates 11 and 13 and all three plates are fixed together bymachine screw 14. These plates may be composed of any metallic, plastic,ceramic or other suitable material. For the purpose of illustration theplates are shown composed of clear plastic material, such as Lucite.

The configuration cut from plate 12 provides a jet interaction chamber22, feedback passage 27, fluid power nozzle 16, apertures 19 and 20 andoutput tubes and 121. The feedback passage is provided with oppositelydisposed nozzles 17 and 18 and orifices 17a and 18a which communicatewith chamber 22. The term orifice, as used herein, includes orificeshaving parallel converging or diverging walls of any conventional shape.Input tube 15 communicates with nozzle 16 and can be threadedly fixed inplate 13. Nozzle 16 forms orifice 16a which communicates with one wallof chamber 22. Apertures 19 and 20 are normally symmetrically spacedrelative to orifice 16a. Flow divider 26 is substantially symmetrical toorifice 1a. Tip 29 of divider 26 defines one side of apertures 19 and 20which have identical cross-sectional areas. A pair of oppositelydiverging walls 22a and 22b forming chamber 22 join the outer Walls oftubes 120 and 121, respectively and define the opposite side of theapertures. The end of input tube 15 extending from plate 13 can beconnected to any conventional source of fluid glider pressure indicatedby reference numeral 800 in Tube 44 inserted in tube 120 scoops olf aportion of the fluid flowing into that tube. Tube 44 can be threadedlyor otherwise fixed into the end of tube 120. Porous plug resistors 123and 124 may be inserted into the ends of tubes 120 and 121 in order toachieve or maintain stable oscillation.

When power nozzle 16 initially issues fluid, the resulting power jetentrains particles adjacent to its flow and tends to evacuate thechamber through which it flows. If there is a chamber wall such as wall22a and 22b near one side of the stream the wall will impede the flow ofparticles to the stream. Thus the space between the stream and the Walltends to become evacuated. The pressure of particles on the oppositeside of the stream tend to force the stream towards the wall. As thestream moves toward the wall the evacuation process becomes moreefficient. This action which produces boundary layer lock-on isregenerative and the stream is forced against the wall.

As the power jet issues from the orifice 17a it strikes the divider 26.The stream is slightly turbulent so more of it goes on one side ofdivider 26 than the other. This causes a stronger boundary layercondition on one side than the other so all of the stream will becontained in either aperture 19 or 20. The stream tends to evacuate theentire chamber 22, but is more effective in evacuating the regionbetween the stream and the closest wall. Assume, for purposes ofillustration, that because of stream turbulence, power jet is moreeflicient in evacuating fluid from wall 22a than from wall 2211.

As the power jet flows out aperture 19 and tube 120 a counter flow isinduced in tube 121. Initially fluid will be evacuated from bothorifices 17a and 18a and flow out feedback passage 27. However, sincemore fluid is flowing across orifice 17a, the fluid is evacuated moreefficiently from that orifice so the flow at the orifice 1811 willreverse and a pressure wave will proceed from orifice 18a to orifice 17aat the speed of sound in the local medium.

Similarly a rarefaction wave will proceed from orifice 17a to orifice18a reducing the differential pressure which tends to force the streamtowards orifice 17a. The rarefaction wave arrives at orifice 18a at thesame time the pressure wave arrives at orifice 17a. The combined effectof a reduced pressure at 18a and an increased pressure at 17a occurringin phase with the stream issuing from nozzle 16 is to shift the streamfrom aperture 19 to aperture 20. Then there is a sudden reversal offlow. Where the fluid flow was flowing into tube 121 it is now flowingfrom that tube and where the fluid was flowing from tube 120 it is nowflowing into that tube. Consequently, where the flow was flowing fromorifice 17a of feedback passage 27 it is now flowing into that orifice.This fluid also creates a pressure wave which travels at the speed ofsound in the medium through the feedback passage 27 to orifice 18a whereit issues as a jet to cause the power jet to shift into aperture 19again.

Three factors control the frequency of oscillation and these are: thespeed of sound in the fluid at the particular pressure temperature anddensity; the length of the feedback loop; and the transit time for thepower jet to flip from one chamber wall to the other.

As the speed of sound and the transit time of the power jet only changeslightly for moderate changes of pressure temperature and density, thefrequency of oscillation is mainly governed by the length of thefeedback loop. The frequency of oscillation is very stable if changes inthe ratio of the power jet pressure to the outlet pressure are slightand the temperature and density are substantially constant.

It has been determined that oscillation is most readily obtained if theapex of the flow divider or split-tor is from three to eight orificewidths downstream. This is a region where the power jet is readilyflipped from one side to the other by blocking the stream outlet.

As would be expected from the above, the tendency to oscillate is alsoenhanced by partially blocking the stream outlets because by partiallyblocking the outlet the pressure which feeds down the boundary layersbetween the bounding wall and the power jet is raised. This raisedpressure assists the signal in the feedback loop to flip the power jet.

Beveling the exit end of the bounding walls facilitates the counterflowin the boundary layer and increases the tendency to oscillate. While theunit is shown with a feedback loop, a well constructed oscillator willoscillate at its highest frequency with the feedback loop removed andthe control passages open to the atmosphere. Presumably the waves aretransmitted through the shortest path in the atmosphere instead of beingrequired to follow a longer path through the feedback loop.

There are several things which decrease the tendency of the unit tooscillate or prevent it from oscillating. These items fall into twoclasses -(1) Attenuating or reflecting the rarefaction and compressionwaves and,

(2) Increasing the memory of the bistable element, that is decreasingits tendency to switch when the outlet is blocked.

Under the first category, the tendency to oscillate is deii creased by afeedback loop which expands and contracts under the action of therarefaction wave and the compression wave. This effect will producegreater attenuation of the waves and extends the wave front. Long narrowpassages have a similar effect. Sharp bends and right angle turnsreflect the rarefaction and compression waves. By this means the wavescan be prevented from reaching the opposite orifice in the correct phaserelationship. Such means can thusly be used to effectively preventoscillation.

Under the second heading placing the apex of the flow divider orsplitter twelve or more orifice widths downstream from the exit of thepower jet enhances the stability of the unit. With the splitter in thisregion, it is extremely diflicult to make the unit oscillate. If hooksare provided in the chamber walls vortices, created within these hooksby fluid flowing thereover will tend to prevent feedback down theboundary layer adjacent the hook. As a consequence the memorycharacteristic is increased and the tendency to oscillate decreased.

Oscillator 10 is employed for producing constant successive fluid outputpulses so that tube 44 can receive such pulses and convey them to asecond component, fluid binary counter lili).

It will be understood that any fluid pulsing means can be used forproducing constant pulses and that, oscillator 10 is merely one exampleof fluid oscillator suitable for use as a source of constant fluidpulses. However, since it is an object of this invention to eliminatemoving parts it is preferable that the sonic oscillator employed be onewhich has no moving parts.

Fluid-operated binary counter lltlt) (FIGS. 4 and 6) consists of aseries of three fluid pulse converters 16th:, will) and little.Converter 160a (FIG. 2) consists of a fluid memory system 150,encompassed by phantom lines as shown, and a tube and nozzle connectionreferred to by numeral 16%.

Fluid memory system includes a fluid supply or power nozzle 170, a pairof control nozzles 18% and 1% and apertures 21% and 211. Orifices 181and 191 formed by control nozzles 189 and 1% respectively, communicatewith chamber 226?. Fluid is supplied to system 150 by nozzle 179. System15% is basically a fluid amplifier with a memory characteristic.

The term memory refers to the characteristic of the fluid stream fromnozzle 170 to persist in trying to exhaust into that aperture 211? or211, through which it is initially directed by fluid flow from one ofthe control nozzles 13%) or 1%, respectively, even after the controlfluid flow has ceased from the control nozzles and despite partial ortotal blockage of discharge from the output tube associated withaperture Zlll or 21 .1.

In memory system the flow divider blade is split in half forming twosections 261 and 2&2. The memory feature is achieved in system 150 byspacing the tips 391 and 392 of sections 261 and 262 respectively, asubstantial vertical distance as viewed in this figure from orifice 171.This distance should be at least equal to twelve widths of orifice 1'71.Such spacing of the tips of the flow dividers from the orifice 171 willensure that the fluid stream from nozzle 179 will remain locked-on tothe chamber wall 221 or 222 against which it was initially deflectedeven though the output tube from which the stream would issue is heavilybackloaded. Alternatively,

the chamber walls may be provided with sharp changes of slope in orderto achieve greater lock-on and memory.

Orifice 171 should preferably be positioned slightly closer to onechamber wall 221 or 222 than the other, depending upon which aperture210 or 211 is to initially receive fluid from nozzle 1'70. Theasymmetrical positioning of orifice 171 with respect to chamber wall 221or 222 insures that when flow is initiated in nozzle it will always flowinto one aperture. Flow into one preselected aperture 210 or 211 canalso be effected by inclining the nozzle slightly or by rounding oneside of the orifice 171. The fact that flow from nozzle 170 can bedirected initially into one of the apertures permits reset of converter100a. The reset feature will be discussed in greater detail hereafter.

Control nozzles 18th and 191 are respectively connected to the ends oftubes 240 and 250 which form the uppermost ends of the nozzle and tubeconnection 16th Peripheral walls 241 and 251 define the outer walls ofthe tubes 240 and 250 which terminate at orifice 350 formed by nozzle360. Walls 241 and 251 are setback from orifice 350 so that fluidissuing from nozzle 360 will lock-on to either of these walls inaccordance with the boundary layer control principle discussed above.

While walls 241 and 251 are setback from either side of orifice 3541,their respective opposite inner walls 242 and 252 intersect to form aflow divider 260 as shown. The tip 390 of divider 26b is verticallyaligned, as viewed in the figure, with the center of orifice 350 formedby input nozzle 360. Tube 44 is the single input tube which communicateswith input nozzle 360 and with the output tube 121 of oscillator It isdesirable to have nozzle orifice 350 and walls 241 and 251 symmetricalso that slight flow from tubes 250 and 240, or vice-versa, induced by apressure differential in the tubes will positively influence the fluidjet from input nozzle 360 into the proper tube.

The required pressure differential induced in tubes 240 and 250 iscreated when the fluid stream from nozzle 170' is deflected against wall222 of chamber 220 by a jet from nozzle 180, for example. A lowerpressure region will consequently be created across orifice 191, innozzle 190, and in tube 250- as a result of fluid flow over wall 222,than exists across orifice 181, in nozzle 180 land in tube 240. When thefluid stream from nozzle 170 is deflected against chamber wall 221 byfluid issuing from control nozzle 190, a lower pressure region will becreated in nozzle 18% than exists in nozzle 190.

The vacuums which can be successively created across the orifices of thecontrol nozzles and in the control nozzles themselves as fluidsuccessively flows over opposite chamber walls create pressuredifferentials in tubes 240 and 250 which are utilized to producealternating switching of the fluid stream, as will be evident from thefollowing description.

As the fluid stream issues from nozzle 179 it will en'- train fluid inchamber 220. The fluid stream from nozzle 170 can be positioned slightlycloser to wall 222 than to wall 221, by for example, positioning nozzle170 slightly closer to wall 222, inclining nozzle 170 slightly towardwall 222 or otherwise, as discussed above. If the fluid stream isslightly closer to wall 222 then to wall 221 the pressure on the side ofthe fluid stream toward wall 222 will be slightly lower than on the sideof the fluid stream toward wall 221. This difference in pressure causesthe fluid stream to move slightly toward wall 222 and the movementtowards wall 222 causes a further reduction in pressure on the side ofthe fluid stream toward wall 222. The stream bends until it finallylocks-on to this wall.

With the fluid stream from nozzle 170 locked-on to the chamber wall 222the pressure in nozzle 190 and tube 250 will be lower than the pressurein nozzle 180* and in tube 240. The difference in pressure in tubes 24(1and 250 will induce a small fluid stream to flow from 180 around tip 391to nozzle 190. The velocity and mass flow induced is insufficient tounlock the fluid stream issuing from nozzle 170 from the wall 222. If afluid pulse is thereafter fed to nozzle 360 the lower pressure existingin tube 250 and the small fluid stream flowing from 240 to 250 causesall the fluid from nozzle 360 to flow into tube 250. Fluid flowing intotube 250 issues from nozzle 190. This flow supplies fluid to theboundary layer along Wall 2221;. Suflicient fluid is supplied to theboundary layer to raise the pressure therein until the differential inpressure is no longer sufficient to hold the stream onto wall 222.Consequently, the stream from nozzle 170 will swing to the center ofchamber 220 ewacuating fluid between it and wall 221 until the decreasein pressure between the stream and wall 221 causes the stream to lock-onto that wall. Thus, the stream issuing from nozzle 170 will switch fromaperture 211 into aperture 210. A bistable switching action occursbetween apertures 21% and 211 since memory system will cause a definiteswitching of the fluid stream from the power nozzle as a result ofalternating fluid jets issuing successively from each of the controlnozzles 150 and 190.

Since the fluid stream from power nozzle 170 is now issuing fromaperture 210, a lower pressure region is created across orifice 181 ofcontrol nozzle with the result that after tube 250 ceases to supplyfluid to nozzle 180, tube 240 will be at a lower pressure than tube 250.Consequently, the next fluid pulse from input tube 44 will flow intotube 240 where it can issue from nozzle 1180, thereby switching thefluid stream into output aperture 211.

As described above with regard to the operation of oscillator 10, wherethe fluid stream from nozzle 170 is switched from aperture 210' to 211or vice versa compression and rarefaction waves are induced in tubes 240and 250. These waves arrive between Walls 241 and 251 at the same time.The waves reflect from the wall and are intermingled in the regionbetween divider 390 and nozzle 359. The phase relationship of theoriginal waves is also distorted. The combined result is that the wavesdo not have suflicient magnitude or the proper phase relations .ip toswitch the fluid stream issuing from nozzle 170 from one outlet apertureto the other.

Slot 65, formed between the opposite edges of divider sections 261 and262 is open to the atmosphere or to a capacitance and resistance, ifrequired, and insures stability of the deflected stream under heavybackloading because flow from the atmosphere down slot 65 will alwaysallow a higher pressure to exist on the side of the fluid streamopposite the boundary layer region. This is so because ordinarily thepressure in the amplifier and in the boundary layer region will alwaysbe less than atmospheric. The combined eflect of thelowerethan-atmospheric pressure in the boundary layer region and theatmospheric pressure on the other side of the fluid stream in chamber220 ensures that the stream will be held against the chamber wall 221 or222 towards which it was deflected by a control jet even though outputtubes 223 and 224 are heavily loaded by tubing or valves. If thepressure in the amplifier is greater than the surrounding atmosphere aclosed container forming a fluid capacitance should be connected to slot65. The capacitance will periodically store fluid and issue it into slot65 so as to aid the stability of deflection of the power jet.

The fluid signal supplied to tube 44 will be a series of fluid pulsesfrom oscillator 10 while the fluid stream issuing from nozzle 170 willbe alternately deflected from one aperture to another in system 150, andthus from output tube 223 to tube 224 as a consequence of the inducedpressure diflerential in the nozzle and tube connection 160. Tubes 240,250 and nozzle 360 thusly cooperate to convert sequential fluid pulsesreceived from oscillator 10 into alternating fluid pulses. It should benoted that no moving parts are required to perform the conversionfunction. Also because of the memory characteristic system 150, once thefluid stream locks-on to one wall of the chamber 220, it remainslocked-on to that wall in the absence of the fluid from both controlnozzles 180 and 190. Since memory system 150 is basically a pure fluidamplifier, the large energy stream from nozzle 17 0 will be deflected byjets from the control nozzles 180 or having lesser energy.

Pulse converters 10011 and 100s (FIGS. 4 and 6) are identical in shapeand size to converter 1001: described above and are modified by theaddition of tubes 45 and 46.

Tubes 45 and 46 are designed and positioned to scoop ofl a portion ofthe fluid stream entering the apertures of converters 100a and ltltlbrespectively. Tubes 45 and 46 communicate with each input nozzle 3456band 3600 of converters and lllilc, respectively, causing deflection ofthe fluid stream issuing from the power nozzles 17% and 1'7tlc. Alsosuccessive pulses of fluid entering nozzles 36% and Selle of convertersltlilb and little will cause successive deflections of the streamissuing from these nozzles into opposite tubes 246a, 25311, 24%, 25%,Mile and 2580 of the tube connection, as discussed above with regard toconverter 100a. Fluid resistors which may take the form of porous plugs70a, 71a, 70b, 71b, 70c, 710, are fitted into the output tubes in orderto insure proper backloading of the output tubes and deflection of thefluid into those tubes.

Tube 75 is connected to source Still and to each input tube 150a, 1501)and 1590 of the converters. Tube 76 is connected to tube 75 and to inputtube of oscillator 19. When valve Sill is turned on fluid will be fedfrom source 800 to the oscillator and to each converter of counter 100.

Source Silt) may be any source of pressurized liquid or gas orcombination thereof. The orifice of each power nozzle in each converter1tltla, 1W1; and little is positioned slightly closer to one charnberWall than the other. If the orifices are closer to Walls 222a, 2221; and2220 than to Walls 221a, 22 1b and 2210, after valve flit-1 is turned onthe fluid stream issuing from nozzles 17%, 17% and 1'7 he will lock-onto Walls 222a, 2221) and 2220 and issue from output tubes 224a, 2124band 224s. This is known as the turn-on position of the counter.

If a single pulse of fluid from oscillator 10 is received by nozzle 366ain converter 1100, it will issue from tube 250a and thus from nozzle190a. Fluid from nozzle 19th: will deflect the stream from nozzle 17th:into aperture 210a and hence into tubes 223a and 45. Fluid entering tube45 issues from nozzle 36% of converter liltlb. The fluid output ofconverter ltlilb will be flipped from tube 22412 to tubes 2123b and 46.Fluid entering tube 46 is conveyed to nozzle 36th: of converter Mile.The output of converter is thusly deflected from tube 22 4c to tube2230.

If the fluid stream supplying nozzle 360a is interrupted by a secondpulse, the flow pattern in counter 10% Will change again. Since thepulsing of the fluid stream entering nozzle 360:: of converter lllflacauses switching of the fluid stream from tube 45 to tube 224a fluidwill issue 'from output tube 224a. Since neither converter ltiflb norlittle can receive a fluid pulse from converter ltllla, these latterconverters continue to issue fluid from tubes 22311 and 2230.

When the flow to nozzle 36th: in converter 100a is interrupted or pulsedfor the third time, the flow in converter lilila is switched from tube224a to tube 223a and 45. Fluid flowing through tube 45 causes the fluidissuing from nozzle 17% in converter lltlllb to switch from tube 223?)to tube 22%. In the absence of a pulse to nozzle 36% converter liltlccontinues to issue fluid from tube @230.

When the fourth fluid pulse is supplied to converter liiila convertersltlila and Milk have the same flow pattern as they did when the firstpulse was received by the counter, whereas the fluid issuing fromconverter little is caused to switch from tube 2230 to tube 224s.

Counter 1%, as shown, is capable of counting up to seven successivefluid pulses before it resets. As will be evident, the reset occurs onthe seventh pulse after the initial or turn-on pulse is received. Thosein the art will appreciate that by merely increasing the number of fluid.flow will issue from tubes 222a, 222k and 222.0.

"characteristics will be 0, 0 and 1.

characteristic as indicated by the table.

19 22411 and 2 240, and the value 0 has been assigned to represent fluidflow from each output tube 223a, 223b and 2230.

Referring now to Table I below, there is shown the output fluid patternsof the various pulse converters a, 10Gb and lime which comprise counter100. The lefthand column of the table lists the successive oscillationsof oscillator 10. The values 1 and 0 represent that output tube of eachconverter from which fluid is flowing. For any given number ofoscillations of oscillator 10 the characteristics of the counter can bedetermined. The term oscillation, as used herein, refers to one completecycle of deflection of the fluid stream in the oscillator from eitheroutput tube.

Table I Output of Fluid Pulse Converters Signal Turn-On. 1 1 1 1stOscillation" 0 0 0 2nd Oscillation. 1 0 0 0 l 0 0 O 1 1 0 0 1 0 1 1 1 1O 0 0 9th Oscillation 1 0 0 10th Oscillation. O 1 0 11th Oscillatiorn 00 1 12th Oscillation. 1 0 0 13th Oscillation. 1 0 1 14th Oscillation 1 11 At signal turn-on that is, when valve 801 is turned so that fluid fromsource 800 is supplied to tube 70 and, hence, to each fluid nozzle a,1701) and .1700, fluid Since the value "1 has been assigned the flowoutput of these tubes the output characteristics of the converters willbe 1, 1 1. After the first oscillation of oscillator 10, since the fluidWill issue from tubes 221a, 221i: .and 221c the output flowcharacteristic is represented by three O s. At the second oscillation,fluid will issue-from tubes 2220, 2221b and 2220, as stated above, andhence the counter At the seventh oscillation, the counter will reset andthe cycle repeats.

Tabulating the output flow characteristics of the counter such as shownin table I is helpful since once the output flow characteristics of thecounter are known fluid-operatcd'readout components can be suitablyconnected to the output tubes of the counter which will read-out anyarrangement or sequence of numbers 1 and 0'.

As stated above, for any given number of oscillations of oscillator -10,the counter will have an overall output It is possible to connect to theoutput tubes of the counter a fluid-operated readout unit in the form ofa fluid AND component 300 which will detect and indicate by means of afluid output pulse from one output tube of the AND component when anyparticular combination of pulses issues from counter 100. The particularcombination of pulses is of course related to the time required beforeoscillator 10 produces enough pulses to produce that particular flowcharacteristic in the counter. The particular connection of the inputtubes of the AND component to the output tubes of the counter willdepend upon the characteristic of the output flow pattern.

fices 364, 374, and 384 are formed by nozzles'363, 373 and 383,respectively, and communicate with jet interaction chamber 333.Apertures 343 and 353 also communicate with jet interaction chamber 333,as shown. Output tubes 443 and 453, see FIG. 3, communicate withapertures 343 and 353. Tubes 443 and 453 are the AND and NOT outputtubes respectively, of component 3011. Tube 443 divides to form twotubes 463 and 473. Porous plugs 483 and 484 may be inserted as shown inorder to provide proper backloading of the AND component.

As the fluid stream issues from nozzle 363 it will entrain fluid inchamber 333. The fluid stream from nozzle 363 may be positioned closerto wall 473 than to wall 463, for example, by positioning orifice 364substantially closer to wall 473 or by inclining nozzle 363 towards Wall473. Orifice 364 may be positioned to the right of the tip of divider393 to facilitate shifting the stream since wall 463 can be setback farenough from orifice 364 to prevent boundary layer lock-on fromoccurring. As fluid issues from nozzle orifice 364, because wall 473 iscloser to the stream than wall 463, the pressure on the side of thefluid stream toward wall 473 will be lower than on the side of the fluidstream toward wall 463. This difference in pressure causes the fluid jetfrom nozdle 363 to move toward wall 473 and the movement towards thiswall causes a further reduction in pressure on the side of the fluidstream toward that wall. The stream bends until finally it lockson tothis surface. Fluid from nozzle 363 will never lock-on to wall 463because this wall is setback far enough from orifice 364 to preventboundary layer lock-on from occurring.

As the pressure in the boundary layer between the fluid stream and thewall 473 decreases, the tendency of the fluid stream to remain locked-onto that wall increases, as will be apparent. Consequently, in theabsence of an input signal from nozzle 373 the stream from 363 flowsalong wall 473 into aperture 353 and out NOT tube 453.

If tube 224a does not receive a fluid signal while tube 2.240 isreceiving such a signal, the jet from nozzle 363 enters aperture 353since wall 463 is too far away from orifice 364 to provide a surfaceupon which the stream can lock-on to.

Fluid flowing into tube 224a issues as a jet from orifice 374. This jetsupplies fluid to me boundary layer between 473 and the fluid streamfrom nozzle 363. Suificient fluid must be supplied to the boundary layerto raise the pressure therein until the differential in pressure is nolonger sufficient to hold the stream onto wall 473. Asthe magnitude ofthe input signal increases the stream from nozzle 363 will be deflectedto the right of chamber 333. Thus, the stream issuing from nozzle 363will switch from aperture 353 into aperture 343 in the absence of flowfrom nozzle 383.

Nozzle 383 is positioned to issue fluid from orifice 384 to deflect thefluid stream into aperture 353 if tube 224!) receives fluid. Thus onlyif there is no flow into tube 224b will fluid issue from tube 463.

The presence of both input signals to nozzles 363 and 373 and theabsence of a signal to nozzle 383 will be iudicated by fluid flowingfrom output tube 463.

Fluid capacitances and/or fluid resistances in the form of porous plugs,for example may be included in the tubes of the system to shape andregulate the pulses as is known to those skilled in the art.

If additional pulse converters are incorporated into the systemadditional AND-NOT components will be needed to detect the increasednumber of signals forming a particular pattern. However, the signalsfrom the additional AND-NOT components can be combined by means of otherAND-NOT units to form a single output if desired.

It will be evident from the foregoing that output tube 463 will onlyissue a fluid pulse when a 1, "0, 1 pattern is produced by counter 100.

Binary counter 100 has a natural repetitive cycle of seven oscillations.Reset occurs after the seventh oscilla 12 tion. If the timer is to havea longer or shorter repetitive time cycle, then reset must occur after agreater or lesser number of pulses have been received from oscillator10.

If desired an additional AND component 500, FIG. 5, may be employed toeifect resetting of counter after a predetermined number of oscillationsof oscillator 10. In this component also, boundary layer lock-on isutilized to achieve the AND or NOT function. As can be seen from FIG. 5,component 50%) consists of two input nozzles 563 and 583 and associatedinput tubes 575 and 463 which feed fluid input signals into respectiveinput nozzles. Orifices 564 and 534 are formed by nozzles 563 and 583,respectively, and communicate with jet interaction chamber 533.Apertures 543 and 553 also communicate with chamber 533, as shown.Output tubes 521 and 522 communicate with apertures 543 and 553. Tubes521 and 522 are the NOT and AND output tubes respectively, of component5%. Tube 75 is connected to tube 521 so as to receive fluid therefrom asshown in FIG. 6.

Fluid flowing into tube 463 issues as a jet from orifice 584. This jetsupplies fluid to the boundary layer between wall 568 and the fluidstream issuing from nozzle 563. Source 304) supplies fluid to tube 575.Suflicient fluid must be supplied to the boundary layer to raise thepressure therein until the differential in pressure is no longersufiicient to hold the stream from nozzle 563 onto wall 560. As themagnitude of the input signal increases the stream from nozzle 563 willbe deflected to the lower portion of chamber 533 by fluid from nozzle583. Thus, the stream issuing from nozzle 563 will switch from aperture521 into aperture 522. In no case will fluid from nozzle 575 lock-on tochamber wall 570 since this wall is set back a considerable distancefrom orifice 564. The presence of both input signals will be indicatedby fluid flowing from output tube 522.

Fluid flowing from nozzle 533 interrupts the flow from source 8% intotube 75. Fluid flow to counter 100 is thereby momentarily stopped andconsequently flow to nozzle 583 subsequently ceases because of theabsence of a signal from AND component 300. Counter 100 is thusly reset.Since component 300 is no longer issuing an output signal which woulddeflect flow from source 800 into tube 522, tube 75 again receives fluidflow from this source and the cycle begins once again in the counter.

Those skilled in the art will realize that fluid capacitors and fluidresistors may be used in the system to shape and regulate the number ofoutput pulses. Such capacitors and resistors may exhaust to atmosphereor to other sources of pressure which themselves can providepredetermined pressure levels and differentials in the system.

In the absence of a fluid jet from nozzle 563, fluid issuing only fromnozzle 583 will be deflected by curved wall section 593 and issue fromtube 522. As an alternative to curved wall section 593, a spill-outaperture may be positioned opposite orifice 584.

Since the fluid timer consists basically of a fluid oscillator, a seriesof pulse converters, and a fluid AND logic component, any other suitablefluid-operated system which performs the same or an analogous functionmay be substituted for the components shown and described in thisapplication. For example the fluid pulse converter may also take theform of a fluid pulse converter disclosed in my copending patentapplication Serial No. 60,763 filed October 5, 1960, now matured intoU.S. Patent 3,001,- 698, issued Sept. 26, 1961. The AND component maytake the form of one of the AND components disclosed in patentapplication Serial No. 96,623, filed March 17, 1961 of Billy M. Hortonand myself.

I claim as my invention:

1. A fluid-operated timer comprising, a source of pressurized fluid,oscillating means connected to said source for producing periodic fluidpulses, means limiting said fluid within said oscillating means to aplane of oscillation of said fluid, fluid-operated means for convertingsaid pulses into a fluid flow pattern, the characteristics of said flowpattern being dependent upon the number of pulses received, meanslimiting said fluid flowing within said fluid-operated means to a singleplane, means connected to said source and said fluid-operated means forresetting said fluid-operated means after a predetermined flow patternis created by said fluid-operated means and means limiting said fluidflowing within said resetting means to a single plane.

2. A fluid-operated timer comprising, means for providing timed fluidpulses, fluid pulse counting means connected to said source forconverting said fluid pulses into fluid flow patterns, fluid-operatedreadout means connected to said counting means for reproducing a fluidsignal upon the occurrence of certain of such flow patterns, afluid-operated component connecting said readout means and said counterfor resetting said counting means upon receiving a fluid signal fromsaid readout means, and fluid limiting means in each of said means forproviding timed fluid pulses, said fluid pulse counting means, saidfluid-operated readout means and said fluid-operated component confiningsaid fluid to a single plane within each of said means.

3. In a fluid-operated timer, a fluid power source, a fluid oscillatormeans for producing timed fluid pulses, said fluid oscillator having apower input means and a pair of pulse output means, a plurality ofcounter means for converting said timed fluid pulses into fluid flowpatterns, each of said counter means having a fluid pulse input means, afluid power input means and a pair of flow output means, a readout meansfor determining a preselected number of fluid pulses including aplurality of flow input means and a pair of readout output means, a

reset means having a power input means, a readout input means, a poweroutput means and an exhaust means, and first means for connecting saidfluid power source to said power input means in said fluid oscillatormeans and in said reset means, second means for connecting one of saidpulse output means of said fluid oscillator means to said pulse inputmeans of a first of said plurality of counter means, third means forconnecting one of said flow output means of said first counter means tothe power input means of a second of said counter means, fourth meansfor connecting the other of said flow output means of said first countermeans to a first one of said flow input means of said readout means,fifth means for connecting the other of said flow output means of saidsecond counter means to a second one of said flow input means of saidreadout means, sixth means for connecting one of said pair of readoutoutput means to said readout input means in said reset means and seventhmeans for connecting said power output means of said reset means to saidfluid power input means in each of said counters.

References Cited in the tile of this patent UNITED STATES PATENTS2,760,511 Greeff Aug. 28, 1956 2,970,226 Skelton et a1. Jan. 31, 19613,006,144 Annett et a1. Oct. 31, 1961 3,010,649 Glattli Nov. 28, 19613,016,066 Warren Jan. 9, 1962 FOREIGN PATENTS 606,733 Canada Oct. 11,1960

1. A FLUID-OPERATED TIMER COMPRISING, A SOURCE OF PRESSURIZED FLUID,OSCILLATING MEANS CONNECTED TO SAID SOURCE FOR PRODUCING PERIODIC FLUIDPULSES, MEANS LIMITING SAID FLUID WITHIN SAID OSCILLATING MEANS TO APLANE OF OSCILLATION OF SAID FLUID, FLUID-OPERATED MEANS FOR CONVERTINGSAID PULSES INTO A FLUID FLOW PATTERN, THE CHARACTERSTICS OF SAID FLOWPATTERN BEING DEPENDENT UPON THE NUMBER OF PULSES RECEIVED, MEANSLIMITING SAID FLUID FLOWING WITHIN SAID FLUID-OPERATED MEANS TO A SINGLEPLANE, MEANS CONNECTED TO SAID SOURCE AND SAID FLUID-OPERATED MEANS FORRESETTING SAID FLUID-OPERATED MEANS AFTER A PREDETERMINED FLOW PATTERNIS CREATED BY SAID FLUID-OPERATED MEANS AND MEANS LIMITING SAID FLUIDFLOWING WITHIN SAID RESETTING MEANS TO A SINGLE PLANE.